import java.util.Arrays;
import java.util.Scanner;

public class Test {


    public static String func0(String str) {
        //有bug

        char[] tmp = new char[101];
        //遍历字符串
        int k = 0;
        for (int i = 0; i < str.length(); i++) {
            char ch = str.charAt(i);
            boolean bool = true;
            //遍历数组
            for (int j = 0; j < tmp.length; j++) {
                //存在则不存入
                if (ch==tmp[j]) {
                    bool = false;
                    break;
                }
            }
            if(bool) {
                tmp[k]=ch;
                k++;
            }
        }

        int count = 0;
        for (int i = 0; i < tmp.length; i++) {
            if(tmp[i]!='\u0000') {
                //System.out.print(tmp[i]+" ");
                count++;
            }
        }
        char[] arr = new char[count];
        for (int i = 0; i < count; i++) {
            arr[i] = tmp[i];
        }

        String s = new String(arr);
        return s;

    }
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextLine()) { // 注意 while 处理多个 case
           String str = in.nextLine();
            String tmp = func0(str);
            System.out.println(tmp);
        }
    }
    public static String func(String str) {
        boolean[] arr = new boolean[127];
        StringBuilder sb = new StringBuilder();
        for(int i = 0;i<str.length();i++){
            char ch = str.charAt(i);
            if(arr[ch]==false) {
                sb.append(ch);
                arr[ch] = true;
            }
        }
        return sb.toString();
    }
    public static void main777(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextLine()) { // 注意 while 处理多个 case
            String str = in.nextLine();
            String ret = func(str);
            System.out.println(ret);
        }
    }
    public static void main555(String[] args) {
        int[] A = {4,5,6,0,0,0};
        int[] B = {1,2,3};
        merge(A,3,B,3);
        for (int i = 0; i < 6; i++) {
            System.out.print(A[i]+" ");
        }
    }
    public static void merge(int A[], int m, int B[], int n) {
        int i = m-1;
        int j = n-1;
        int k = m+n-1;
        while(i>=0 && j>=0) {
            if(B[j]>A[i]) {
                A[k]=B[j];
                k--;
                j--;
            }else {
                A[k]=A[i];
                k--;
                i--;
            }
        }
        //A数组
        while(j>=0) {
            A[k]=B[j];
            k--;
            j--;
        }
    }
    public static void main22(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String str = scanner.nextLine();
        String tmp = func2(str);
        System.out.println(tmp);
    }
    public static String func2(String str) {
        StringBuilder sb = new StringBuilder();//新字符串，作为返回值
        boolean[] arr = new boolean[124];
        for (int i = 0; i < str.length(); i++) {
           char ch = str.charAt(i);
           if(arr[ch]==false) {
               sb.append(ch);
               arr[ch] = true;//标记目标点
           }
        }
        return sb.toString();
    }


    public static void main11(String[] args) {
        char[] arr = {'a','b','c','d',' '};
        String str = new String(arr);
        System.out.println(str);
    }

    public static void main2(String[] args) {
        int[] A = new int[]{1,2,3,0,0,0};
        int[] B = {4,5,6};
        int m =3;
        int n = 3;
        for(int i = 0;i<n;i++) {
            A[m+i]  = B[i];
        }
        //排序
        for(int i = 0;i<A.length-1;i++) {
            for(int j = 0;j<A.length-1-i;j++) {
                if(A[j]>A[j+1]) {
                    int tmp = A[j];
                    A[j] = A[j+1];
                    A[j+1] = tmp;
                }
            }
        }
        for (int i = 0; i < A.length; i++) {
            System.out.print(A[i]+" ");
        }
    }


    public static void main3(String[] args) {
        char[] tmp = new char[5];
        char ch ='a';
        tmp[0]='a';
        tmp[1]='b';
        for (int i = 0; i < tmp.length; i++) {
            System.out.print(tmp[i]+" ");
        }

    }

    public static void main000(String[] args) {
        String str = func2();
        System.out.println(str);
    }
    public static String func2() {
        //有bug
        Scanner scanner = new Scanner(System.in);
        String str = scanner.nextLine();

        char[] tmp = new char[101];
        //遍历字符串
        int k = 0;
        for (int i = 0; i < str.length(); i++) {
            char ch = str.charAt(i);
            boolean bool = true;
            //遍历数组
            for (int j = 0; j < tmp.length; j++) {
                //存在则不存入
                if (ch==tmp[j]) {
                    bool = false;
                    break;
                }
            }
            if(bool) {
                tmp[k]=ch;
                k++;
            }
        }

        int count = 0;
        for (int i = 0; i < tmp.length; i++) {
            if(tmp[i]!='\u0000') {
                //System.out.print(tmp[i]+" ");
                count++;
            }
        }
        char[] arr = new char[count];
        for (int i = 0; i < count; i++) {
            arr[i] = tmp[i];
        }

        String s = new String(arr);
        return s;
    }


    public static void main1(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String str = scanner.nextLine();
        char[] tmp = new char[7];

        for (int i = 0; i < str.length(); i++) {

            char ch = str.charAt(i);
            boolean bool = true;
            for (int j = 0; j < tmp.length; j++) {
                //存在则不存入
                if (ch==tmp[j]) {
                    bool = false;
                    break;
                }
            }
            if(bool) {
                tmp[i]=ch;
            }
        }
        //打印数组有效部分
        for (int i = 0; i < tmp.length; i++) {
            if(tmp[i]!='\u0000') {
                System.out.print(tmp[i]+" ");
            }
        }
        String s = new String(tmp);
        System.out.println(s);
    }
}
